1. The Discovery of Ionophores: An Historical Account 2. Tetracyclines and Daunorubicin 3. Interaction of Metal Ions with Streptonigrin and Biological Properties of the Complexes 4. Bleomycin Antibiotics: Metal Complexes and Their Biological Action 5. Interaction between Valinomycin and Metal Ions 6. Beauvericin and the Other Enniatins 7. Complexing Properties of Gramicidins 8. Nactins: Their Complexes and Biological Properties 9. Cation Complexes of the Monovalent and Polyvalent Carboxylic Ionophores: Lasalocid (X-537A), Monensin, A23187 (Calcimycin), and Related Antibiotics 10. Complexes of D-Cycloserine and Related Amino Acids 11. Iron-Containing Antibiotics 12. Cation-Ionophore Interactions: Quantification of the Factors Underlying Selective Complexation by Means of Theoretical Computations